Electrical insulator



E. K. MALME 2,870,245 ELECTRICAL INSULATOR Filed NOV. 30, 1956 E 57 hi IIZ Q T" E/zrzer K. Md/JJZG United States Patent ELECTRICAL INSULATOR Elmer K. Malme, St. Charles, Iii. Application November 30, 1956, Serial No. 625,330 Claims. (Cl. 174--175) This invention relates to an electrical insulator and more particularly to an electrical insulator for use in connection with wiring installations where high potentials at comparatively low powers are involved. While the insulator forming the subject matter of the present invention has wide application, it is particularly adapted for use in connection with fence charger systems used on farms and ranches.

As is well known, fence charger systems provide means for impressing a high potential upon a conductor in the form of a wire or metal fence to teach animals to remain within a desired area. Inasmuch as the power generated by a fence charger is comparatively low and the potential is high--of the order of about 10,000 volts-it is desirable to provide adequate insulation to prevent the potential impressed upon the fence or conductor from being dissipated.

This requirement is especially necessary when long lengths of fence are to be charged. In such case, unless adequate insulation is provided, it is found that the potential drops off rapidly along the length of the fence and results in a substantial portion of fence being electrically inoperative.

Inasmuch as fence charger installations are made with unskilled labor in mind and the installations are accomplished under adverse conditions, it is desirable to provide insulation means which are simple to install. In addition to the above requirement, it is important that the insulator itself be rugged, have a high degree of efficiency and be so constructed that it may be put into use with minimum tools. An additional requirement is that the insulation means be relatively cheap. The insulator forming the subject matter of the present invention fulfills the above requirements to a remarkable degree.

The insulator in general provides long surface paths to reduce leakage of current. In addition, the construction is rugged and permits a wire to be snapped into the in sulator without any tools. The mounting of the insulator is accomplished in simple fashion, the insulator being sufficiently adaptable to accommodate a large variety of mountings.

In order that the invention may be understood, reference will now be made to the drawings wherein an exemplary embodiment is shown. It is understood that variations may be made without departing from the scope of the invention as defined by the appended claims.

Figure 1 is a side sectional view through the center of the new insulator secured in position and supporting a conductor.

Figure 2 is a perspective view of the insulator of Figure 1, certain portions being broken away.

Figure 3 is a top view of the insulator shown in Figures 1 and 2.

Figure 4 is a view from one end of the insulator illustrated in Figures 1 to 3 inclusive.

Figure 5 is a view from the other end of the new insulator.

Figure 6 is a section along line 44 of Figure 3 but modified to show the mounting hook removed.

Figure 7 is a viewof the new insulator, unmounted, showing the sloping end face for jaw spacing control.

The insulator forming the subject matter of the present invention may be made of a number of different materials having some flexibility. However, it is preferably of a polyethylene material. This has highly desirable characteristics in maintaining a high surface resistance to high potential. Instead of polyethylene, other materials available in the market such as Teflon, Kel-F may be used. These latter materials are modified polyethylene compounds.

The insulator embodying the present invention comprises hub portion 10 having bore 11' extending through the length thereof. Hub portion 10 has one end 12 where bore 11 is reduced at 13. Reduced bore portion 13 is eccentric to bore 11 and the two bores may have what is shown in Figure 1 as the top portions alined.

Hub 10 and portion 12 are provided with wall portions 15 and 16 extending outwardly from the hub and annularly around the hub. Wall portions 15 and 16 have oppositely disposed faces 17 and 18 to provide a spool-like construction. Faces 17 and 13 are generally smooth except for a pair of oppositely disposed jaws 19 and 20, extending for a small angular extent around the hub. Jaws 19 and 20 extend laterally from bore 11 in alinement with the direction of offset of reduced bore portion 13.

laws 19 and 26 have substantially flat inside faces 21 and 22 opposite the hub of the insulator. laws 19 and 20 are provided with outer faces 23 and 24 sloping outwardly from each other. The separation between opposed faces 17 and 18 of jaws 19 and 2t) is substantially smaller than the spacing between opposed faces 17 and 18. When properly mounted, as shown in Figure 1, the jaw separation is smaller than in the unmounted condition of the insulator. laws 19 and 29 do not have circular symmetry for both the inside and outside faces thereof.

In order to reinforce walls 15 and 16 of the insulator, a suitable pattern of reinforcing ribs is provided. Referring first to Figure 5, an end view of wall 16 shows boss 28 extending outwardly from wall 16. The end face of boss 28, in the unmounted condition of the insulator, as illustrated in Figure 7, slopes away from the perpendicular, the slope being away from jaws 19 and 25 to provide a wedge face. From boss 23 massive rib 29 extends in the direction of jaw 20. Transversely of rib 29 and near the periphery of boss 23 are laterally disposed ribs 31 and 32. Generally T-shaped structure 33 extends from boss 28 opposite rib 29. Additional ribs 35 and 36 extend from boss 28 generally parallel to ribs 31 and 32.

Wall portion 15 has, on the outside thereof as illustrated in Figure 2, a generally similar pattern of ribs formed thereon. The insulator has hub portion 39 ex tending from wall portion 15 and flaring to form insulator mounting portion 40. Insulator mounting portion 40 has inside face 41 provided with a number of massive protuberances 42 and 43 extending away from each other on opposite sides of bore 11. Perpendicular to the line joining protuberances 42 and 43 are protuberances 44 and 45. Protuberances 44 and 45 are on a line which is generally parallel to the radius passing from the axis of the insulator outwardly toward jaws 19 and 20 as illustrated here. Protuberance 44 is in longitudinal alignment with the jaws. Between protuberances 33 and opposing boss 29a of wall 15 hub 39 may be provided with elongated rib 46.

Mounting portion 40 has outer face 48. This face may be generally flat and is provided with a pair of gen erally semi-circular recessed portions 50 and 51 respec- ,tively. The two recessed portions are disposed at right angles to each other and intersect at bore 11. Recessed portions 51) are opposite protuberances 42 and 43 on the inside face of this wall. Recesses 51 are opposite protuberances 44 and d5. It will be noted that recesses 50 stop short of the edge of the mounting portion while recesses 51 extend to the edges thereof.

The insulator may be secured in position in a variety of ways. Thus as one example, bolt 55 having hook end 56 may be used to secure the insulator to pipe 57. Instead of pipe 57, there may be a post. Bolt 55 can be threaded through the bore of the insulator and the insulator is secured tightly in position by wing nut 57. With such a mounting, the insulator may be disposed so that jaws 19 and 24) are properly oriented. The curved portion of hook 56 will be accommodated by one portion of recess 50'in the insulator. It is, of course, possible to turn the insulator 90 around its axis and have jaws 19 and 2% extend sideways rather than up from the insulator. In such case, hook portion 56 may be accommodated by recesses 51.

Instead of a bolt or book, a rivet may be used. The rivet may support any suitable kind of a metal mounting strap which may be nailed to a tree or attached to a support.

The supporting means for the insulator, such as threaded bolt 55 or rivet, may be used to compress the insulator axially. Preferably bolt 55 has about the same diameter as reduced bore portion 13. Nut 57 has sufficient area to engage the end face of boss 28. Thus when nut 57 is drawn up the compressive force on the insulator is concentrated on jaws 19 and 20 and tends to bring them closer. The slope of the end face of boss 28 provides a wedge action which channels the compressive force to jaws 19 and 20.

The conductor to be secured may be threaded through or forced past the jaws after which it is locked into position. Because of the reinforcing pattern of the various ribs, jaws 19 and 20 will be maintained in position to lock the conductor unless considerable force is applied to open the jaws.

It is also possible to mount the insulator by threading a nail or spike longitudinally through the insulator and simply driving the nail or spike into a support such as a tree or a post without any attaching strip. In all cases, the supporting means will have an enlarged head portion corresponding to the wing nut 57 for locking the insulator into position and pressing against boss 28. Since the insulator supporting means are generally of strong materials as steel and will therefore have considerable strength, the mounting of the insulator in position will tend to compress the insulator and maintain the jaws in position.

The various reinforcing bosses and ribs provide maximum surface leakage paths. In addition, the leakage paths will tend to drain water off. It is possible to combine wall portion 15 and mounting portion 40 in one massive portion. However this will raid to reduce the length of the leakage paths from ground, which may be represented by the surface of pipe 57 and the conductor within the insulator jaws. It is understood that the insulator has some flexibility and will permit springing wire 26 into position without damage to the insulator.

What is claimed is:

l. A high potential insulator of molded plastic having at least some flexibility, said insulator comprising a hub, a pair of spaced externally extending thin wall portions to form a spool with the hub, said wall portions having spaced faces and being provided with a pair of opposed jaws, said jaws extending inwardly of said walls and being spaced substantially less than the diameter of a conductor to be supported by the insulator, said hub portion having an axial insulator mounting bore, said insulator being adapted to be pressed against a support with some mounting means such as a bolt or nail passing through the insulator bore and supporting the insulator, said hub having one end face sloping to form a wedge surface with the orientation being directed so that axial compression of the insulator will result in forcing the jaws closer.

2. The insulator according to claim 1 wherein said wall portions are provided with reinforcing ribs adjacent the jaws on the outer surfaces for increasing the stiffness of the material at the jaws.

3. The construction according to claim 1 wherein the insulator has its free bore and reduced in section and laterally offset toward the jaws.

4. The construction according to claim 1 wherein the mounting portion has recesses in the other end face, said recesses extending to the bore, said recesses being adapted to accommodate the curved part of a metal hook or screw eye.

5. The construction according to claim 1 wherein said jaws extend in a generally straight line offset from and perpendicular to the bore.

References Gated in the file of this patent UNITED STATES PATENTS 2,447,251 Huette Aug. 17, 1948 

